Bone fixation procedures often require the insertion of a bone screw transversely though a bone. In such cases, it is necessary to assess the depth of a hole formed through the bone. Existing measurement devices include a calibrated rod having a single hook provided on an end thereof. In operation, the rod is inserted through the bone hole and, after emerging from an opposing end of the bone hole, the rod is retracted until it abuts against a blind edge adjacent the opposing end. The disadvantage of such devices is that hooking the edge of the bone hole is quite difficult, especially when measuring smaller diameter holes. There is a need for a hole-depth measuring instrument that provides a fast and accurate measurement. There is a further need for a measuring instrument which firmly engages the opposing distal edge of the bone hole to allow for a precise measurement of the bone hole.